From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=0.6 required=5.0 tests=BAYES_00,FREEMAIL_FROM,
	FROM_WORDY autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,f20f5dfbb5c26c12
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2003-12-03 13:04:12 PST
Path: 
 archiver1.google.com!news2.google.com!newsfeed2.dallas1.level3.net!news.level3.com!crtntx1-snh1.gtei.net!news.gtei.net!newsfeed1.easynews.com!easynews.com!easynews!newspeer1.nwr.nac.net!solnet.ch!solnet.ch!irazu.switch.ch!switch.ch!news.belwue.de!newsfeed01.sul.t-online.de!newsmm00.sul.t-online.com!t-online.de!news.t-online.com!not-for-mail
From: "Vincent Smeets" <No.Spam@T-Online.de>
Newsgroups: comp.lang.ada
Subject: Re: discriminant in constraint must appear alone
Date: Wed, 3 Dec 2003 22:02:52 +0100
Organization: T-Online
Message-ID: <bqlj28$erv$07$1@news.t-online.com>
References: <bqiq1m$uis$00$1@news.t-online.com>
Mime-Version: 1.0
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
X-Trace: news.t-online.com 1070485385 07 15231 8QQSGNQ1JiyXSqYf 031203
 21:03:05
X-Complaints-To: usenet-abuse@t-online.de
X-ID: TlvMSZZJYegLeiZ4SrjnkbSepAJsoICj9o3IJOO8ufnJuRb3UvBN88
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 6.00.2800.1158
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165
Xref: archiver1.google.com comp.lang.ada:3118
Date: 2003-12-03T22:02:52+01:00
List-Id: <comp.lang.ada>

Thanks for your answers,

After evaluating the possibilities, I wil stick to:
    B : String (1 .. D);
and waist memory and having no constraint check. I am using it in a smal
program which I am writing. I can control my self in not violating the
constraints.

Giving the record two discreminants isn't nice for general use because
there needs to be a lot of comments describing the relation between the
discreminants. The type needs to be controled type to implement the
checking between the discreminants. The checking will be done at
run-time, not at compile-time.

Defining the type as a controlled type and using dynamic allocation for
the arrays is too mush overhead for my problem.

The best solution would be a change in the language. Is there something
foreseen for the new version of Ada?

Thanks,
Vincent Smeets


"Vincent Smeets" <No.Spam@T-Online.de> schrieb im Newsbeitrag
news:bqiq1m$uis$00$1@news.t-online.com...
Hallo,

I want to define a discriminated record type with two arrays. One array
only half the size of the other. Below is the type definition that I
want to use.

   type R (D : Positive) is
      record
         A : String (1 .. D);
         B : String (1 .. D / 2);
      end record;

This type definition can't be compiled by the GNAT compiler. It gives
the error message
    "discriminant in constraint must appear alone"
for the record component B. I know this isn't correct Ada, but how
should I define the type in a correct way?

I have defined B as
    B : String (1 .. D);
and only used the first half of it, but this way I waist memory and
can't have any Ada constraint checks for component B. So this is not the
way I want to do it.

Are there other possiblities?


-- 
Thanks,
Vincent Smeets